Project Summary/Abstract: Despite recent advances, CLL as the most common leukemia remains a largely incurable disease. The goal of the proposed project is to elucidate the ability of the lentiviral vector (LV) to provide efficient and clinically feasible delivery system for CD40-ligand (CD154), a very well known stimulator of T cells in chronic lymphocytic leukemia (CLL). This approach using LV-CD154 is expected to be superior to existing immune therapies using adenoviral vectors and will be the basis for a future improved immune therapy for CLL and potentially other hematological malignancies. In Aim 1, we will develop SIN lentiviral vector that expresses CD40-ligand, as well as control vector expressing GFP. All vectors will contain the Drosophila melanogaster dNK-B10 gene using the E2A cleavage peptide sequence which will increase vector's safety. LV will be manufactured according to standard procedures and quality control tested prior to release for testing. In Aim 2, we will test the transduction efficiency of SIN.LV.CD154 and SIN.LV. GFP in vitro using primary CLL cells, and cell lines from different low grade lymphomas (CLL/SLL, MCL and FL) In addition, we will assess duration of expression of the transfected gene and test the relative potency of targeted cell stimulation with soluble CD154 versus cell bound CD154. During Phase I, we propose to generate SIN-LV containing CD154 payload and to investigate its efficacy in CLL cells. Ultimately, during Phase II, the SIN-LV-.CD154 will be tested in preclinical and clinical settings. During Phase III, this therapy will be commercialized for CLL and possibly other hematological malignancies like mantle cell lymphoma and acute myeloid leukemia. The generated results will provide a basis for the development of a better and novel therapy for CLL and will significantly challenge the existing immune therapies using adenoviral vectors, mostly inadequate for providing stable and successful long term therapeutic activity. Project Narrative: Despite recent advances, chronic lymphocytic leukemia(CLL) as the most common leukemia remains a largely incurable disease. Modern treatment options include novel drugs like purine analogues, monoclonal antibodies, transplantation strategy and immunotherapy. In this proposal, we expect to generate novel immune therapy of CLL that is likely to quickly expand to treatment of other hematological malignancies. This therapy will have significant relevance for leukemia and lymphoma patients, ultimately positively impacting public health in general. [unreadable] [unreadable] [unreadable]